The group -- which included one Republican Congressman -- took some criticism for meeting with the president of Syria, a nation with which the Bush administration has cut diplomatic ties. Ellison says it's important for the U.S. to keep lines of communication open.

"If we don't talk and there's no negotiation, no dialogue, how do we know whether they're making any steps toward eliminating their role in connection to what we regard as terrorist groups?" said Ellison. "And how do we know whether they've attempted to make any progress at all?"

Ellison said the delegation shared the message that the U.S. wants to work with the people of the region to stop terrorism.

"We all need to get people to the point where they resolve political conflict around a table, as opposed to over a battlefield," Ellison said. "Dialogue is a precursor to understanding. Dialogue is a precursor to agreement. So, we have to talk to people, especially people we have disagreements with, because how else do we have any hope to resolve disagreements?"

Ellison is the first Muslim elected to Congress. He says his presence in the delegation led by House Speaker Nancy Pelosi was a symbol of religious diversity and tolerance in the U.S.